Preterm, premature rupture of membranes (PPROM) is the largest contributor to perinatal morbidity and mortality, accounting for 40-60% of the residents in the neonatal intensive care unit. Because fibroblasts are the cell type responsible for collagen synthesis and providing strength to the fetal membrane, fibroblasts in the fetal membrane are a likely target for membrane weakening leading to PPROM. The research goal of this proposed RO3 is to understand the proliferation rates, mitogenic responses, and effects upon collagen synthesis in recently isolated fibroblasts from the amnion and from the chorion in response to growth and immune factors endogenous to the fetal membranes. TGFbeta1 (Transforming Growth Factor beta1) and INFgamma, (Interferon gamma) are powerful modulators of fibroblast proliferation, differentiation and collagen synthesis and are present in the placenta and fetal membranes throughout pregnancy. The hypotheses to be tested in this proposal are: a) TGFbeta1 and INFgamma," modulate proliferation of amniotic and chorionic fibroblasts; b) TGFbeta1 and INFgamma alter collagen synthesis and fibroblast differentiation to altered phenotypes. To test these hypotheses, fibroblasts will be isolated from the human fetal amnion and chorion separately in order to pursue the following Specific Aims: 1) Does TGFbeta1 and INFgamma exposure of primary amniotic fibroblasts and chorionic fibroblasts produce mitogenic effects? and 2) Does TGFbeta1 and INFgamma exposure of primary amniotic fibroblasts and chorionic fibroblasts alter fibroblast differentiation and collagen production? In PPROM, fibroblasts in the fetal membrane could respond inappropriately to normal signals, resulting in abnormal proliferation and altered collagen synthesis. These changes would ultimately result in localized membrane weakening and fetal membrane rupture. Thus, fibroblasts in the fetal membranes are likely targets in the etiology of premature rupture of the fetal membranes. This research on fibroblasts from the amnion and from the chorion would lead to an understanding of responses to fibroblast modulators, which are present in the fetal membrane during pregnancy.